This invention relates to oral compositions for use as dentifrices, topical solutions or pastes, disintegratable tablets, oral bands, cavity sealers, gels for ultrasonic treatment, gels for iontophoresis, prophylactic pastes, dental flosses, desensitizers of teeths, mouthwashes in the form of liquids, tablets, powders or gels, chewing gum and the like. More particularly, this invention relates to oral compositions containing stannous fluoride and a phytic acid compound such as phytic acid, its alkali metal or alkaline earth metal salts and phytin which are effective dental caries inhibitors capable of increasing the acid resistance of the tooth enamel upon application.
Various compounds have been proposed as effective ingredients for inhibiting dental caries. In particular, water-soluble fluoride compounds are known as being effective in inhibiting dental caries. When fluoride compounds are applied to a tooth surface, fluorine is taken up by the tooth enamel to enhance the acid resistance of the tooth enamel. Among such fluoride compounds most widely used are sodium monofluorophosphate, sodium fluoride and stannous fluoride. These compounds, however, are not fully effective to inhibit dental caries. Fluoride compounds containing stannous ions, for example, stannous fluoride, are proved as being more effective in improving the acid resistance of the tooth enamel than those containing no stannous ions, for example, sodium fluoride. These water-soluble stannous ion-containing fluoride compounds are effective to some extent, but their efficacy is not found to be very high. Further, the increased acid resistance of the tooth enamel is kept for only a limited period of time after treatment because the efficacy relatively readily disappears out as a result of the self-cleansing action of saliva, brushing, mastication and the like. Moreover, the stannous ion-containing fluoride compounds are chemically unstable.
In addition to fluoride compounds, a number of compounds have been investigated on their dental caries inhibition. One approach uses sodium or calcium phytate alone to reduce the solubility of hydroxyapatite in an acid, but has not generally been evaluated as sufficiently effective. Other examples using phytic acid are British Pat. No. 1,384,375 which discloses an oral hygiene composition comprising a divalent metal salt of phytic acid such as calcium phytate mixed with a monofluorophosphate, and British Pat. No. 1,408,922 which discloses an oral composition comprising two phases which are isolated from one another and/or do not react with one another, one phase containing a water-soluble calcium compound and the other phase containing a water-soluble organic or inorganic phosphoric acid compound such as phytic acid and optionally, a water-soluble fluoride compound. However, the evaluation of these compositions has not been widely established.